Ambient Air Pollution and Incident Stroke

描述（由申请人提供）：心血管疾病发病率和死亡率与环境细颗粒空气污染 (PM2.5) 水平升高之间存在有充分的关联。中风是心血管疾病的常见表现，也是美国死亡、住院和长期残疾的主要原因。 PM2.5 还可能增加缺血性和/或出血性中风的风险，但很少有研究专门讨论这一假设，而且结果仍然模棱两可。该文献中的其他重要差距包括：识别特别易受影响的个体；评估PM2.5成分种类、气态污染物（CO、NO2、SO2和臭氧）和特定空气污染源的影响；以及影响的时间范围的描述。我们建议以前所未有的细节评估接触个别环境污染物和污染物混合物与参与妇女健康倡议的 159,643 名绝经后女性和参与健康专业人员后续研究的 45,358 名男性的中风风险之间的关联。具体来说，利用这两个国家前瞻性队列的数据，我们将：（1）评估长期（即：年）和短期（即：天）暴露于环境污染物对缺血性和出血性中风风险的影响，（2）评估患有糖尿病和其他中风危险因素的参与者是否特别容易受到这些影响，（3）检查关联强度是否因缺血性中风亚型而异，（4）在一种新颖的多污染物框架。为了实现这些目标，我们将使用经过验证的最先进的地统计模型来估计每个参与者对 PM2.5、PM2.5 成分、气态污染物和污染物混合物的暴露情况，并将每个人的暴露情况与缺血性和出血性中风的风险联系起来。与现有研究相比，该提案具有多个优势，包括两个特征明确的研究人群、每次中风事件的详细数据、大样本量、地理多样性、联合检查短期和长期影响的能力、减少测量误差的新颖统计方法，以及在新颖的多污染物框架内同时评估多种污染物的机会。通过更好地量化环境空气污染物和污染混合物与特定中风类型之间的关系，并通过识别易感人群，该项目的结果将有助于制定对中风预防具有重要影响的监管政策，并可能有助于为未来机制研究的规划提供信息。

DESCRIPTION (provided by applicant): There is a well-documented association between cardiovascular disease morbidity and mortality and increased levels of ambient fine particulate air pollution (PM2.5). Stroke is a common manifestation of cardiovascular disease and a leading cause of death, hospitalization, and long-term disability in the United States. PM2.5 may also increase the risk of ischemic and/or hemorrhagic stroke, but few studies have specifically addressed this hypothesis and results remain equivocal. Other important gaps in this literature include: identification of especially susceptible individuals; evaluation of the effects of PM2.5 component species, gaseous pollutants (CO, NO2, SO2, and ozone) and specific air pollution sources; and delineation of the time scale of effects. We propose to evaluate in unprecedented detail the association between exposure to individual ambient pollutants and pollutant mixtures and the risk of stroke among 159,643 post-menopausal women participating in the Women's Health Initiative and 45,358 men participating in the Health Professionals Follow-Up Study. Specifically, using data from these two national, prospective cohorts we will: (1) evaluate the effects of long- term (i.e.: years) and short-term (i.e.: days) exposure to ambient pollutants on the risk of ischemic and hemorrhagic stroke, (2) assess whether participants with diabetes mellitus and other stroke risk factors are especially susceptible to these effects, (3) examine whether the strength of association varies by ischemic stroke subtypes, and (4) evaluate these associations within a novel multi-pollutant framework. To accomplish these aims we will estimate each participant's exposure to PM2.5, PM2.5 component species, gaseous pollutants, and pollutant mixtures using validated state-of-the-art geostatistical models, and relate each individual's exposure to the risk of ischemic and hemorrhagic stroke. This proposal offers several advantages over existing studies, including two well characterized study populations, detailed data on each stroke event, large sample size, geographic diversity, the ability to examine short-term and long-term effects jointly, novel statistical methods to reduce measurement error, and the opportunity to assess multiple pollutants simultaneously within a novel multi-pollutant framework. By better quantifying the relationship between ambient air pollutants and pollution mixtures and specific stroke types, and by identifying susceptible populations, the results of this project will contribute to regulatory policy with important implications for stroke prevention, and may help to inform the planning of future mechanistic studies.